1. Field of the Invention
This invention relates to a method of finishing a laminated decorative sheet for imparting thereto a permanent embossed shape wherein a laminated decorative sheet having surface properties similar to those of a laminated thermo-setting decorative sheet is in the first place once molded under heat and pressure by means of a method of using a flat smooth metal plate or of using a continuous molding machine consisting of rolls having plane surfaces and a steel band, without using any embossing metal plate or the like in the time of this molding under heat and pressure, and afterwards, the thus molded sheet is passed through heated embossing rolls under pressure, or alternatively, after the molded sheet has been preheated, the thus preheated sheet is passed through embossing rolls under pressure which have not been heated, whereby an embossed laminated decorative sheet having surface properties similar to those of an embossed thermo-setting decorative laminate may be prepared by post-finishing embossing method.
2. Description of the Prior Art
Various methods have hitherto been known for manufacturing laminated thermo-setting decorative sheets having embossed patterns where the desired patterns are imparted on the surfaces of the laminated sheets at the same time of molding the sheets under heat. These conventional techniques include, for example, a method of molding a laminating sheet under heat and pressure where engraved metal plates are used in the molding, a method where a thermo-setting resin is previously applied on or impregnated into an emboss patterned paper or fabric or the like and then is cured under heat, and thus prepared patterned plate which has been subjected to release-treatment is interposed between a smooth metal plate and the impregnated paper, and a method for transferring mesh patterns where a wire net, a fabric or the like is put on the impregnated paper after the wire net, etc. have been subjected to release-treatment, or otherwise via a releasing film between the wire net, etc. and the impregnated paper.
However, these conventional methods involve various defective problems. In particular, in the case of embossing metal plates, it is necessary to simultaneously mold a lot of sheets and therefore, a lot of embossing plates which are expensive must be prepared for the embossing. In the case of superposing a lot of rugged plates, the pressure is apt to become uneven. In the method of using patterned plates or other interposition matters, the steps are complicated and the range for selecting the desired patterns is limited. Moreover, when a post-finishing for imparting embossed patterns is tried to the laminated thermo-setting decorative sheet (or board) which has once been molded under heat and pressure and which has an even surface, by pressing the laminate with an embossing plate or by passing the same through embossing rolls, the embossing can hardly been attained and further cracks are often caused in the resulting laminate by the embossing treatment because of the fact that the core or the underlaid material (the plywood hard board, etc.) have already been pressed and contracted together with the surface layer of the laminate in the molding of the laminate and that the surface resin layer has already been cured.